Bandstructure engineering in 2D materials using Ferroelectric materials

Engineering Bandstructure of two-dimensional (2D) materials is one of the strong requirements to increase their effectiveness in various applications. Among many methods, constructing van der Waals heterostructures (vdW_HTS) is one of the proven method to tune the bandstructure of the 2D materials. In this work, HTS has been constructed using ferroelectric (FE) materials to get advantages of its unique properties such as built-in polarization and reversibility of polarization under moderate external field. Among FE materials, In2Se3 is chosen due to its good optical and electrical properties. Heterostructure was constructed by encapsulating bilayer graphene (BLG) and MoS2 with In2Se3 layers to impose an electric field on them. There is strong possibility to alter the contact surface of In2Se3 which forms the heterostructure interface, by applying moderate electric field owing to its reversible polarization. Therefore, several heterostructure types based on In2Se3 orientation have been studied and each resulted unique and distinctive band structures for both MoS2 and BLG vdW_HTS. Based on polarization direction heterostructures are categorized as AB, AA and BB. And among them AB and BB vdW_HTS configurations, resulted considerable band gap on BLG. In addition, behaviour of vdW_HTS are thoroughly observed by charge transfer and electrostatic potential analysis to provide an accurate insight.